Photographic emulsions containing unsymmetrical tetranuclear cyanine dyes



PHOTOGRAPHIC EMULSIONS CONTAININGIQUN'SYMMETRICAL TETRANUCLEAR CYANINEDYES Sept. 23, 1952 T R. THOMPSON ,5

Original Filed Dec. 21, 1948 2 sHE'ETs -sfiEf 2 I c n CH3 Fig. 4.

TTORN s Patented Sept. 23, 1952 PHOTOGRAPHIC EMULSIONS CONTAININGUNSYMMETRICAL TETRANILCLEAB QY-.

ANINEDYES Thomas R. Thompson, Binghamton, N. Y., :as-

.signor to General Aniline & Film Corporation, 7 N w York, N- ea?! corpoat on f Delawa Original application December 21, 1948, Serial No.66,575, now Patent No. 2,518,731,'dated August 15, 1950. Divided andthis application April 30, 1949, Serial'No. 90,712

4 :Gla ms- "This invention relates to photographic gelatinosilver-halide emulsions, and more particularly to photographic emulsionssensitized by means of new unsymmetrical tetranuclear cyanine dyescontaining two, internal thiazole nuclei.

Thenseaof sensitizin dyes, particularly inmultilayer. color film, posesmany problems. It is known that sensitizing dyes operate by dyeing thesilver-halide grain. To do this, they must beadsorbed to thesilver-halide. If they are ,displaced from the silver-halide grains,they lose their efiectiveness as ,sensitizers. It is also known thatmany color formers .used in color photography have greater .ailinity forsilverhalides than the sensitizers, and act to displace the same .fromthe silver-halide grains. Qne must, therefore, selecta vsensitizer whichwill not be so displaced.

Another problem arises as regards the migration of the .sensitizers fromone emulsionto another. Where this-ensues, color distortion is theinevitable result. Many proposals have been made-dealing with theanchoring of compounds in silver-halide emulsions, the most noteworthybeing the use of .a long .alkyl chain (see Wilmanns et .al. United.States .Patent 2,186,849).

,It is, therefore, necessary .w-henproviding sensitizers, particularlyfor .color photography, to make certain that they have (1) the propersensitizing power, (2) the ability to withstand displacement fromsilver-halide grains by color formers, and (3) the ability to resistdifiusion from .one sensitized emulsion to .another.

.Efiorts which satisfy the last prerequisite, unfortunately, often leadto compounds which will. notmeet the first two tests. Thus, it is knownthat the sensitizing power of cyanine dyes varies with the .substituent.on the .cyanine .N-atoms. Where, .this substituent is .alkyl, the powerdecreases as. the chainlength. increases. Hence, if a long alkylchain.beused toanchor the v.dye in the emulsion, we end up with a product oflittle or no sensitizing power. The use of otherexpedients to anchorthexlye, on the .other hand,;often gives products incapable ofwithstanding the displacement action of color formers insofar as thesilverhalide grains are concerned. It is thus manifest that theprovision 20f sensitizers having :the necessary prerequisite isv .a.difi'icult problem, .to .say the :least.

.Itis known that many .cyanine dyes :sensitize photographicsilver-halidelemulsions to. high red sensitivity. Most of these dyes,however, are

notsuitabletorsensitizingsilverehalide-emulsions containing .color.ooupling components. fljhis 1s thought to be .due to a h Si aIdisplacement which the sensitizing dye undergoes when'color couplingcomponents are added. .Th'a't .is,i.the sensitizer is adsorbed to thesurface. .otthesilverali e ra n. a d. the with addi i n f color couplingcomponent, ,is displaced therefrom. Moreover, most of the cyanine dyes@1313. incompatible with silver-halide .emnlsion stabilizers, suizh as,for example, memento-substitutedtetra: zo es. r

An object of thepresent invention is tolnrovice photographicsilver-halide emulsions .with m symmetrical tetranuclear sensitizing.dyestufis containing twointernal thiazoleinuclei,

.A further object .is to provide .suchjdycs. fhich are .ireetrom thedisadvantages noted-above; v

.Other objects and advantagesofgthis driven; tion .will become apparentbyreference to-tthe following specification in .which its preferred.details and embodiments ,are described.

This invention ,is based .on the .discovelty tha-t unsymmetricaltetranuclear .cyanine ,dyes taining two internal thiazole nucleinotonl-ysensitize .a. photographic silver-halide emulsioneto high .redsensitivity, but=are also-.compatibleswith color coupling componentsiorthe cyan dye image and ,with ,practically all emulsionstabilizersincluding the .mercaptosubstituted ftetrazoles. In thelattercombination, the sensitizing-action of the dyes is not. impairednordiminished. addition to :these, desirable characteristics, it hasbeen further found-that when the dyesareused in corn llllQtiOl'l-aWithcolor coupling components for the blue-green image, the :spectraleurvesof these dyes show a desirable-gap. :i-n =the;.,green region .of thespectrum, -,i. -e., the .dye. sensit it is more selective to the redspectral region sensitizing capacity of these dyes isjnot; y ma a n nhe. p e nc 0f 69 19 1 1 components for the blue-green image; especia ythose components containing long alkyla, i but is in part rendered moreselective.

Some of the unsymmetrical tetranuclear cya nine'dyes of this inventionwhich 'sensitize'emulsions touthehregions :.of-;longer wavelengths, areof extreme value in'the manufacture of infrared silver-halide emulsionswhich can be exposed through light yellow filters instead of theordinarily used heavy gray filters in view of their low 5 sensitizingpower 'for the green, yellow, and red. An additional advantage of thesedyes is their ability to remain fixed in the layer in which they areoriginally .deposited.

The unsymmetrical tetranuclear cyanine dyes fulfilling the aboveadvantage are obtained. ln

excellent yield and in readily purifiable form by heating a thiazolonecyanine dye salt containing a reactive methylene group adjacent to aketo group with a thiazolone cyanine dye salt intermediate in a suitablesolvent, such as an aliphatic 5 alcohol, e. g., methyl, ethyl, n-propyl,isopropyl and the like, in the presence of a basic condensing agent suchas trimethylamine, triethylamine, pyridine, methyl pyridine, ethylpyridine, quinoline, potassium carbonate and the like, on a steam bathor by heating the reaction mixture at reflux for a period of 5 tominutes.

The dyes obtained by the foregoing procedure are characterized by thefollowing formula:

,2 so=cR- oH=oH),..1-cs C=CH-C\ o=o BIO-C C=CHC B I?! v l al/ wherein Rrepresents hydrogen or an alkyl group, 20 e. g.,'methyl, ethyl, propyl,or butyl, It being only alkyl when n represents 1, R and R" which may bealike or different represent an alkyl, allyl, aryl, or aralkyl group, e.g., methyl, ethyl, propyl, phenyl, naphthyl, tolyl, benZyL'phenethyI,and the like, RT and R which may be alike or different represent analiphatic, aryl, or aralkyl radical," e. g., methyl, ethyl, propyl,butyl, hydroxyethyl, ethoxyethyl, phenyl, tolyl, naphthyl, benzyl,phenethyl, menaphthyl, and the like, n represents a positive integer offrom 1 to 3, X represents an acid radical, e. g., chloride, bromide,iodide, or alkyl sulfate, alkyl p-toluene-sulfonate or perchlorate, Zand 2' represent the atoms necessary to complete a heterocyclic nucleusof thetype contained in cyanine dyes, e. g., oxazoles, thiazoles,selenazoles, and their polycyclic homologues,"such asfthoseof thebenzene, naphthalene; i. e'., naphthiazole and perinaphthiazole, acenaphthene, and anthracene series, pyridine, and 40 its polycyclichomologues, such as quinoline and a and pfnaphthaquinclines,perinaphthiazoles, indolenines, diazines, such as pyrimidines andquinazolines, diazoles (e. g, thio-,B 3'-diazole), oxazolinespyrroiines, thiazolones and selenazolinesfithe polycycliccompounds ofthese series being substituted if desired in the carbocyclic rings withone or more conventional groups, such as alkyl or aryl as below, amino,hydroxy, alkoxy, i. e., methoxy, ethoxy, etc., and methylenedioxygroups, or by halogen atoms, i. e., chlorine, bromine, etc.) Z and Zbeing the same or different depending upon whether R1 and R2 are thesame or different. In other words, Z and Z" may be the same if R1 and Baare different. However, if R; and R2 are the same then Z and Z" must bedifferent.

i The thiazolone dye intermediates utilized as the core'actant with thethiazolone cyanine dye salts arecharacterized bythe following generalformulae} R l H-(CH=CH)s-1-CH=C-S C=CHC 5 I O=C \N/ SN, 1 '7 is is ridwherein R2, R2, and 2 have the same values as R", R' and Z respectively,and X has the same values as above, R4 represents an aryl group of thebenzene and naphthalene series, such as phenyl, chlorophenyl, diphenyl,tolyl, or naphthyl, R5 represents either hydrogen or an acetyl is 2X-group, R6 represents an alkyl or aralkyl group, e. g., methyl, ethyl,propyl, isopropyl, benzyl, fi-phenethyl, and the like, R7 represents analkyl group, e. g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl,etc. and or. represents a positive integer of from 1 to 3, and Yrepresents the atoms necessary to complete a saturated heterocyclicnitrogenous nucleus, such as, for example, piperidine, 5- or'y-pipecoline, pyrrolidine, morpholine, tetrahydroquinoline, and thelike.

The dyestufi intermediates illustrated by For mulae a and c are preparedaccording to the method described in my copending application Serial No.66,571, filed December 21, 1948, now United States Patent 2,535,992, andthe intermediates illustrated by the second Formula I) are preparedaccording to the method described in my copending application Serial No.66,572, filed December 21, 1948, now United States Patent 2536,5387.

The dyestuff intermediates illustrated by Formula a are, in general,obtained by treating a diarylformamidine or its vinylog, such asfi-anilinoacrolein anil hydrochloride or glutaconic aldehyde dianilhydrochloride, in the presence of an acid condensing agent such asaceticanhydride, or in the presence of a basic condensing agent such astriethylamine, or piperidine, with a thiazolone cyanine dye.

The dyestuif intermediates illustrated by For mula b are obtained bytreating a thiazolone cyanine dye with an aliphatic acid anhydride inthe presence of a mixture of py idine and tri ethylamine followed bytreatment with phosphorus pentasulfide to yield the thin derivativewhich is subsequently alkylated with an alkylating agent in the usualway to yield the thioether derivative.

The thiazolone cyanine dyes utilized in preparing the foregoingintermediates and which are condensed with the said intermediates arecharacterized by the following general formula:

t. it x in view of their ketomethylene configuration,'

-' group enolizes to form a hydroxy-ltgroup. aqueous solution ofpotassium iodide. 'I'hgmd,

precipitation with ether. A yield ofi-5.9 grams of 5.. .62" undergoketo-enolatiiutornerism. i. e., the ketoponrmittthemieactimiimixtmerinhmm m' hfiflte The following examplesdescribe the preparauct was purified by washing with water andsu'btionofzfsome of the thiazolone cyanine dye in'tersequently grinding Withiacetone. A yield 10.9 mediates illustrated by Formulae a' and b which'51: grams of; yellow g1istening,;-;crystals melting at areutilizednnthe preparationohthetetranuclear 255-260 C. wasiobtained; Theprbduct iyasfused cyanine dyes; H v with 10 cc. of methylsulfhtesatQfiiC. Ion:l;0.ininutes to yield a thick-solution whicluu'pontreatfilfli v ment with an acetone solution of sodium iodide depositsyellow crystals.

Example In on! Annixltureot.5rg rarns"ot--diphenyi1orinainidine,51grarns'of' the thiazolorie*cyanineidye"cf fthe fol Y., Y ".725;}31'013101'110 anhydride, 10 cc. of triethylamine. and

13 grams of the thiazolone scyanine dye of the f following structure:C=CH-C\ Z and 15 cc. of acetic anhydride was heated at 140.? C. for 30minutes. After cooling, the product was precipitated "witlm etheriandpurifie'diby dissolving-- it in a small amount of methanol ifollowed hy=yellow-green crystals, having a melting point at 213-215 0. wasobtained. I addeillnfiflrtmnsflfl?" H E, QPIQDanoI;.v'llhererwasnhtained '0 o ye ow powder" which decox'n jdse I a Amixture of 9.3 grams of the yellow powder 3 5 and grams ofmethylip-teluenesulfonate was fused at 95 C. for 1 hour. After cooling,the product was washed with ether and' id'iss clyed in; 55 10 C(L-Qfwarmsacetcnez frheifinaiproductfwas? I v prec pitated as the iodideby adding zdicc. of;- A mixture of 75 cc. of pyridine, cc; of pronq tcontaining mm The fpicnic anhydride, 15 cc. of triethylaminef-andd5 P PWashed with Water and Purified by? grams of the thiazolone cyamne dye ofthe followboilingput with isopropanol. A yield of 4.3 grams mgStructure: v 1 of a product melting at 225-228 C. was obtained.

Example IV was heated atzl209 C'zzforifBOtminutes: "Fifteen gramsiofnhosphoruszrientasulfideawer i-addediinpontionsxandttheireactiommixtureistirred emails Q i m C.::-inr::30minutesiu'Tlieipro'chiot wasiisolatedxby: 7 anhydride, 2 cc. oftriethylami'r'ie'; n'rPZW-gram' dye of the- .following a i f f washeated at120? C. or 3 minutes. There were 15 then added 2 grams ofphosphorus pentasulfide and the mixture-heated at 115 C. for 15 minutes.A dark: red oil" was precipitated by the addition of 100cc. of water andwashed with water by decantation. The product was fused with ;3 cc.

of methyl sulfate at 95 C. for 10 minutes to yield 415 grams of ayellow-orange solution which may be employed in dye synthesis.

& ..m1xture 01 0.5 gram of the thiazolone cyanihe dye of. Example 111.03gram of p-anilinoacrolein anil'h'ydrochloride, 10 cc. of methanoL'jinto, cc. of water containing 1 (gram of potassiuin. iodide. Thecrystals were separated and purified byi 'boilingi out with 'isopropylalcohol. 1

Ayield oi 0,4, gram of a product having a melting point at I 270-271 C.was obtained. A methanol solution Ifof the compound has an absorption 1at 540 m l.

- Emma: L

A mixture, of 2.85 grams of gluta conaldehyde dianil hydrochloride, 4.3grams of the thiazolone cyanine dye of Example III,.-1 cc. of piperidineand 50 cc. of methanol was heated at reflux for 30 minutes. The reactionmixture was poured into 300200. of water containing 5 grams of potassiumiodide. The precipitated'product was filtered and boiled out withisopropyl alcohol.

yield o1='3..'7 grams of a compound having a melt-' ing point of 195-198C. was obtained. A methanol solution of -the P product has an 1absorption brown ,precipitate -was ,filtered oif washed with. water, andboiled out with 100 ccaof'isopropyl alcohol. A yield of 20.9 grams ofthe dried and purified product was obtained. The compound is presumed tobe aninner salt characterized by A the following formula:

(11H: (EH,

A miiiture of 2 grams of the above material and 2 grams" ofethylp-toluenesulfonate was fused at=" C. for 30 minutes. The reactionmixture was dissolved in-30 cc. of hot acetone, and 10 cc. of a 10%solution of sodium iodide in acetone was added. After cooling, thecrystals were separated and purified by boiling out with isopropylalcohol. A yield of 1 gram of a product meltins-between 210-213 Cawasobtained;

.The anions of the foregoing thiazolone cyanine dye salt intermediatesmaybe replaced by other e i5; anions; suchas iodide, thiocyanate, orperchlo-' rategby. tieating anialcohol solution 'ofithezdye saltwith-anmqueous oraqueousaai-lcdholsolution "containingla sodium. orpotassiumzsa-lticfrtherde- :s'iredanions. r

The following-examples .rdescrib'e; imdetail: the method *of. preparingthe; symmetricakand .unsymmetrical -:.tetranuclearfcyanine dyesvfromtheioregoing thiazolone cyaninegdye salts yandfidye zs'altintermediateshutitis to beiunderstoodtthat theyrarergivenimerelyi'for.the: purpose of .illustra- 'tlonandiarelnot .to be construed.a'sillmitative.

A mixture of 0.3 gram of p-toluenesulfonate salt of the product ofExample III, 0.3 gram of the thiazolone cyanine dye utilized in ExampleIV, cc. of methanol, and 0.5 cc. of triethyh amine was- 'heated atreflux IE-minutea. "-cc; of 20% sodium bromide in methanol was addedand= the dye-separated on -cooling a-ndswas purified by boiling out withisopropyl alcohol. A yield :of 0.4 gram ofaproduct melting-at 226-7227in methanol was added andl'therdye separatediion cooling and wasvpurified by boiling outwith isopropyl alcohol. A yield of 0:5 gram of aproduct melting at 22542260. was-obtained. In methanol solution this-dyeabsorbs :with a maximum at 627 m r. The dye sensitizes a photographicemulsion with a maximum at .695 my.

A mixture .ofs'0i5 gramottheprodiict. ple V, 20 cc. of :methanoldand 0.5gram of tri- C. was obtained. A methanol solution of this dye absorbswith almaximum at 660 mp When incorporated into a bromoiodo photographic-';.-emu' lsion, the optical sensitization ranges :from

580 to 750. ma.withamaximumhatfmi m .ExampleilX Amixtureof 0.3 .gramofthe ,productoi Exampie II, 0.3 gram of the thiazolone cyanine dyeutilized in Example III, 20 cc. of isopropyl alcohol,

ethylamine; 0.4 gram of a thiazolone cyanine dye of the followingstructure;

were. heated at reflux for 5 minutes. After cooling, the dye crystalswereremoved and purified byaboiling out with 'isopropyl alcohol. A yieldof 025 gram of a product melting at 237-239 C. was obtained. A methanolsolution of the dye,, ab-

sorbs light with two maxima'*at- 420*mp-and 734' mg. The sensitizationof a photo'graphic emulsion "is-extended. 1-, oniimxy im i A mi'xture 0110.55. gramihfithe productzof l -cc. of triethylamine was heatediatreflux -'ample VI, 20 lcceot methanol 3015: cci'ibtatniethmamine, and0.4 gram of a thiazolone dye having n the following formula:

' to 900 m with a S-CH I N-C-CH:

was heated at reflux-for 5 minutes After cooling, the reaction mixturewas poured into 'an tained in excellent yield and in readily purifiableaqueous solution of potassium iodide, the ,dye was separated andpurified by boiling out with isopropyl alcohol. A yield of 0.4 gram of aproduct melting at 2l4-2l8 C was obtained. A methanol solution hasabsorption maxima at 447 and 8l1 m When the dye is incorporated in aphotographic emulsion the sensitization is extended maximum at 850 m Amixture of 0.7 gram of the product of Example VII' and 2 cc. of'methylsulfate was fused at 95 C. for minutes. There were then added 25 cc. ofisopropanol,.3 cc. of triethylamine and form.

While I have disclosed the preferred embodiments of my invention and thepreferred modes of carrying the same into effect, it will be readilyapparent to those skilled in the art that many variations may be madetherein without departing from the spirit thereof. Accordingly, thescope of my invention is to be limited solely by the appended claims.

Iclaim:

1. A photographic gelatino silver-halide emulsion containing anunsymmetrical tetranuclear cyanine dyestufi of the following generalfor- 0.4 gram of a thiazolone cyanine dye having the 40 mula:

1 following formula:

The resulting mixture was heated at reflux for 10 minutes. Aftercooling, the mixture was poured into an aqueous solution of sodiumiodide, and

.the precipitateddye purified by boiling outwith isopropanol. A yield of0.3 gram of a dye melting at 244-251 C. was obtained. A methanolso---Iat' various wavelengths.

lution of the dyeihad an absorption maximum at 623 m When added to aphotographic silver-halideemulsiom'the dye extends the range ofsensitization to 735 m with a maximum at 700 my;

it is" in 2::-

wherein n represents a positive integer of from 1 to 3, R. is selectedfrom the class consisting of hydrogen and lower alkyl, R being onlylower alkyl when n represents 1, R and R" are sealkyl, loweralkoxyalkyl, aryl and aralkyl groups of the benzene and naphthaleneseries, X repre- 'Th'diagramma-tic spectrograms constituting theaccompanying'drawing illustrate the regions of the spectrum to whichsome of the trinuclear oyanine dyes will sensitize a gelatinosilver-halide emulsion containing about 4-5% of silver-halide and theextent of the sensitization Figures 1.to15 of this 'dzalwing illustratethe'sensitizingproperties of sents an acid radical, Z' and Z" representthe atoms necessary to complete a heterocyclic nitrogenous system, andwherein at least one of the groups of radicals R"R" and Z'-Z" are dis- 7"similar.

2. A photographic-gelatino silver-halide cram- 2,611,895: 13 v 14 n r.

sion containing an unsymmetrical tetranuclear cyanine dyestufl of thefollowing structure:

3. A photographic gelatlno silver-halide emulsion containing anunsymmetrical tetranuclear eyanine dyestufi oi the following structure:

4. A photographic gelatlno silver-halide emulsion containing anunsymmetrical tetranuclear cyanine dyestufi oi the following structure:

ErCH=CHj 2 THOMAS E. THOMPSON. REFERENCES crrnn The following referencesare of record in the file of this patent:

UNITED STATESPA'I'EN'IS Number Name Date 2,263,018 Sprague -i. Nov. 18,1941 2,395,879 Kendall et a1. 5 Mar. 5. 1946

1. A PHOTOGRAPHIC GELATINO SILVER-HALIDE EMULSION CONTAINING ANUNSYMMETRICAL TETRANUCLEAR CYANINE DYESTUFF OF THE FOLLOWING GENERALFORMULA: